Tool for working on the wall of a pipe and related method

ABSTRACT

An intervention method for acting on a wall of a fluid pipeline using a tool includes moving the tool inside the pipeline until a pipe segment of the tool is positioned facing a zone of the wall of the pipeline. The method also includes creating sealing upstream and downstream from the zone using first and second seals of the tool so as to seal off an outer portion of a segment of the pipeline around the zone. The method further includes acting on the zone of the wall. The sealing by the first and second seals occurs in two portions of the pipeline so as to define a sealing lock between the two portions of the pipeline. The tool further includes an adjustable propulsion system configured to make use of movement of the fluid in order to move the tool.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY CLAIM

This application claims priority under 35 U.S.C. § 120 as a continuationof U.S. patent application Ser. No. 15/115,260 filed on Jul. 28, 2016,which claims priority under 35 U.S.C. § 365 to International PatentApplication No. PCT/FR2015/050178 filed on Jan. 27, 2015, which claimspriority to French Patent Application No. 1400210 filed on Jan. 28,2014. All of these applications are hereby incorporated by reference intheir entirety.

TECHNICAL FIELD

The invention lies in the field of tools and methods for acting on thewalls of pipelines for transporting fluid, such as pipelines forhydrocarbons in liquid or gaseous form, or indeed pipelines fortransporting water. Generally, the fluid (liquid or gas) is underpressure while the network of which the pipeline forms a part is in use.More particularly, the purpose of such action is to repair the pipeline,or indeed to weld fittings to the pipeline.

The pipelines concerned may be in the open air, or they may be buriedpipelines, or they may be undersea pipelines. While they are in use,which may continue for numerous years, their walls may present defectsdue to phenomena of corrosion or of mechanical attack, and thus be inneed of repair.

As a general rule, a repair needs to be performed by removing pressurefrom a segment of the pipeline on either side of the defect that is tobe repaired, while still allowing the fluid to pass through, since anyinterruption could have severe economic consequences for the operator ofthe pipeline or of the network. The repair is preferably performed afterremoving fluid from the segment on either side of the defect (e.g.removing gas or removing water).

In the same manner, when it is desired to make a weld to the outer wallof the pipeline, it is sometimes necessary to interrupt the flow offluid in the segment in question, in particular in order to avoid thematerial cooling excessively, which would be harmful for the quality ofthe welding and for its durability.

There exist systems, which are expensive and complex to use that aresuitable for removing pressure and discharging the fluid, such asstoppers under load and their associated accessories (stopple,reinforcing saddle, hot tapping, balloons). There also exist systemsinvolving a temporary jumper hose for maintaining transit, which systemsare complex in structure and also complex to handle given theirimplications in terms of operator safety.

Also known is Document WO 2007/141554, which discloses apparatus servingin particular to patch a defect by introducing an inner pipe into thepipeline, the inner pipe being positioned facing the defect, and byintroducing an expandable component that is arranged around the pipe andthat is activated so as to be inflated in order to plug the defect fromthe inside. A variant of the apparatus is also used to put a valve intoplace in the pipeline.

That apparatus implies leaving a voluminous tool in place in thepipeline, and it is therefore not very satisfactory since the pipelineremains partially obstructed after the action has been taken.

Also known is Document WO 03/067134, which discloses apparatus forinterrupting (shutting off) fluid flow in a high pressure pipeline. Theuse of that apparatus requires fluid flow to be interrupted or a branchconnection to be made, which is not satisfactory.

SUMMARY

In this context, the invention proposes an intervention tool for takingaction on the wall of a fluid pipeline, the tool comprising a pipesegment for positioning inside the pipeline facing a zone of the walland one or more first or upstream means for creating sealing between thewall of the pipeline and the pipe segment.

According to a general characteristic, the tool further comprises one ormore second or downstream means for creating sealing between the wall ofthe pipeline and the pipe segment in order to isolate an outer portionof a segment of the pipeline from the flowing fluid between the twomeans for creating sealing, and at least the first or the second meansfor creating sealing are in two portions, defining a sealing lockbetween the two portions of said first or second means for creatingsealing.

By means of such a tool, it is possible to create a sealed peripheralzone (or volume) in a segment of the pipeline facing and in contact withthe zone (or surface) of the wall on which it is desired to take action.

This sealed zone is isolated from the flowing fluid, which can beadvantageous thermally speaking in the context of taking welding typeaction on the wall. However the sealed zone may also, where necessary,be subjected to decompression or indeed emptying in order to take actionon the wall without pressure and indeed without the presence of thefluid, even though the fluid continues to flow through the pipe segment.Thus, the tool enables a pipeline to be repaired (or some other actionto be taken thereon) without interrupting the operation of the network,and it also makes it possible to reduce the time needed for takingaction. Its ease and reliability of use makes this tool particularlyadvantageous compared with the above-mentioned prior art systems. Itshould be observed in particular that there is no external bypasssystem, since such a system is made pointless by the presence of thepipe segment inside the tool.

The locks defined by the two portions serve to improve safety, inparticular for applications in which pressures are high. This applies inparticular for gas transport networks where pressures may be as great as67 bars. The safety provided by the tool is then reinforced, as is thereliability of the intervention process.

In a particular embodiment, the first or the second means for creatingsealing comprise expandable and retractable sealing gaskets, e.g.inflated with oil using an oil/nitrogen accumulator, or expandable bycompression using a system of moving plates.

In an advantageous embodiment, the tool further comprises adjustablepropulsion means for propelling it in the pipeline. These means may becontrollable, and they may also be arranged to make use of the movementof the fluid so as to take advantage of an entrainment phenomenon fordriving the tool. The propulsion means may comprise at least oneadjustable flap installed in the pipe segment. The propulsion means mayfor example be actuated for adjustment and control purposes by means ofa hydraulic system powered by an oil/nitrogen accumulator, by anelectromechanical system powered by batteries, or indeed by acombination of such systems.

In certain embodiments, the tool may also include a system guiding thetool inside the pipeline. The guide system may in particular comprise atleast one wheel or deformable disk at each end of the pipe segment.

In optional and advantageous manner, it is also proposed that the pipesegment includes a length of bellows in order to enable it to travel incurved pipelines.

Advantageously, the tool may include a braking system and/or a systemfor holding the tool in position by contact with the inside wall of thepipeline. This braking and/or position-maintaining system may operate byfriction against the inside wall of the pipeline, contact with theinside wall, or by braking the guide wheels.

In an embodiment, the tool may also include a retarder system suitablefor slowing down the movement of the tool without being capable ofstopping it. By way of example, this system may be of theelectromagnetic type.

Advantageously, the tool may also include a communication systemenabling the tool to be located and controlled remotely from outside thepipeline, e.g. by using electromagnetic waves or sound waves.

In advantageous, but optional, manner, the sealing systems may beconfigured to brake the movement of the tool by rubbing against theinside wall of the pipeline and/or to hold the tool in position bycoming into contact with the inside wall of the pipeline.

The invention also provides a method for acting on the wall of a fluidpipeline by using a tool of the invention, the method comprising a stepof moving the tool inside the pipeline until the pipe segment ispositioned inside the pipeline facing a zone of the wall of saidpipeline, a step of creating sealing upstream and downstream from saidzone respectively by using first and second means for creating sealingin order to seal off an outer portion of a segment of the pipelinearound the zone of the wall (or to seal off a volume defined by the tooland the pipeline), and then, if necessary, a step of decompressing saidportion (or said volume). Finally, the method comprises a step of takingaction on said zone of the wall.

At least the first or the second means for creating sealing are in twoportions, defining a sealing lock between the two portions of said firstor second means for creating sealing.

The action is preferably taken from the outside of the pipe by a humanoperator or by apparatus.

In implementations in which the first or the second sealing means areexpandable and retractable, they are actuated to expand in order tocreate sealing and to retract after action has been taken.

In certain implementations, the tool is propelled by the movement of thefluid.

In certain implementations, the movement of the tool in the pipeline andthe actuation of the sealing means are remotely controlled.

In an implementation, the positioning is performed by using an abutmentplaced inside the pipeline, the method including a prior step of hottapping the pipeline in order to put said abutment into place.

In a particular implementation, the outer portion facing the zone whereaction is to be taken is decompressed by using a valve, the methodcomprising a prior step of hot tapping the pipeline in order to put saidvalve into place.

In an implementation, a braking device, which may include or be includedin the sealing systems acting by friction, may be used in order to brakethe movement of the tool before it reaches the abutment.

In an implementation, a retarder device may be used to slow down themovements of the tool, without necessarily stopping it.

In an implementation, a position-maintaining system that may include orbe included in the sealing system, may be used to hold the tool inposition by making contact with the inside wall of the pipeline.

Finally, it is specified that the step of taking action may comprise,amongst other possible actions: making a repair by a welded patch,making a repair by build-out welding, or welding a fitting to thepipeline.

In an implementation, the method includes decompressing each of thelocks by using a valve.

LIST OF FIGURES

The present invention is described below with reference to theaccompanying figures.

FIG. 1 is a three-quarter view of the tool in an embodiment of theinvention.

FIG. 2 is a longitudinal section of the FIG. 1 tool.

FIG. 3 shows the same section, with the propulsion flap open.

FIG. 4 shows the tool being moved in a pipeline.

FIG. 5 shows the tool being positioned by being blocked by an abutmentin the pipeline, in order to make a repair.

FIG. 6 shows the tool in the FIG. 5 position, after sealing has been putinto place.

FIG. 7 shows the wall of the pipeline repaired, after pressure has beenremoved.

FIG. 8 shows the departure of the tool after the repair has been madeand the abutment moved out of the way.

DETAILED DESCRIPTION

FIG. 1 shows a tool 1 in an embodiment of the invention, in athree-quarter view. It comprises a pipe segment 100, which in thisexample is a rigid circular cylinder with open mouths 101 and 102 thatare plane and lie in planes that are perpendicular to the axis of thecylinder, thereby constituting circles.

Close to the mouth 101, the outside of the pipe segment 100 carriesguide wheels 110 (or guide casters) that are arranged in regular manneraround its circumference, e.g. in a common plane. In the example shown,there are four of them. Similar guide means, in this example other guidewheels 110, are present in the proximity of the mouth 102. Other guidemeans could be used, such as for example guide disks. It is possible tocombine guide means of different types.

Still in the proximity of the mouth 101, on the outside of the pipesegment, there is a first inflatable sealing gasket 120. When inflated,this inflatable sealing gasket 120 is designed to press against theinside wall of the pipeline in which the tool travels. Conversely, whendeflated, the gasket is folded down against the pipe segment 100. Theinflatable gasket 120 constitutes a body of revolution of profile thatis circular or non-circular, e.g. a toroidal body having as its axis ofrevolution the axis of revolution of the pipe segment, and surroundingthe pipe segment. The inflatable sealing gasket 120 can be inflated bymeans of a hydraulic system that is remotely controllable and thatincludes an oil/nitrogen accumulator. It is followed on the pipe segmentat a short distance towards the second mouth 102 by a second inflatablesealing gasket 125, similar to the first, and likewise surrounding thepipe segment 100. Continuing towards the second mouth 102, there is athird inflatable sealing gasket 130 that is once more similar to thefirst two. Finally, a fourth inflatable sealing gasket 135 is presentcoming up towards the second mouth 102. The distance between the thirdand fourth inflatable gaskets 130 and 135 is similar or identical to thedistance between the first and second inflatable gaskets 120 and 125,whereas the distance between the second and third inflatable gaskets 125and 130 is greater.

Other sealing means could be used, such as gaskets that expand bycompression or O-rings or lip gaskets capable of expanding so as to bepressed against the inside wall of the pipeline. Gaskets that expandunder compression may comprise elastomer elements suitable for beingexpanded by a wormscrew mechanism or a hydraulic system having movableplane or conical plates serving to compress elements made of elastomer.

Instead of being constituted essentially by a rigid cylinder, the pipesegment may be constituted by two rigid cylinders connected together bya bellows, in order to enable the tool to travel along a pipeline thatpresents curves such as bends.

FIG. 2 shows the same elements as can be seen in FIG. 1, in a sectionview on a plane containing the axis of revolution of the tool 1. It canbe seen that the four inflatable gaskets are installed in groovesprovided for this purpose in the surface of the pipe segment 100. It canalso be seen that the guide wheels 110, whether close to the mouth 101or to the mouth 102, are all configured in the same direction in orderto make it easier for the tool to travel in the pipeline in a particulardirection. These wheels may be movable radially in order to provide goodguidance in spite of geometrical variations to be encountered inpipelines (manufacturing tolerances of the tubes, welds, curves, localdeformations, . . . ). It is also specified that in the embodimentshown, the guide means 110 lie between the corresponding mouth (101 or102) and the nearest inflatable gasket (120, 135), but that the guidemeans could be positioned elsewhere on the tool.

The tool also has propulsion means that are constituted in this examplein particular by an adjustable flap 140 placed inside the pipe segment100, halfway between the two mouths 101 and 102. The flap 140 is shownin its closed position in FIG. 2, thereby providing the tool withmaximum drive by the fluid, while in FIG. 3 it is shown in its openposition, thereby minimizing drive and making it easier to stop thetool. The flap 140 is motor-driven to pass from one of its positions tothe other or to adopt an intermediate position, and to conserve theposition it has adopted while the tool is moving with the stream. Itthus provides a variable “windage” function depending on its degree ofopening. The flap 140 thus enables the tool 1 to move inside thepipeline with the fluid, in the same direction as the fluid, by makinguse of the movement of the fluid to provide a drive phenomenon. The tool1 also has a motor system for the flap 140, or the flaps if a pluralityof flaps are used, and optionally, but not necessarily, an on-boardsource of energy. It is specified that instead of one or more flaps, itis possible to use one or more diaphragms or one or more adjustablegrids. Furthermore, the system is designed to be remotely locatable orcontrollable by means of a communication system between the tool and theoutside of the tube.

The tool 1 may also include an electromagnetic retarder (not shown)acting on the wheels to enable the speed of the tool to be reduced, butthat does not enable the movement of the tool to be stopped completely.

The tool 1 may also include a braking system acting by friction againstthe inside wall of the pipeline (not shown).

The tool 1 may also include a system for holding the tool in a staticposition inside the pipeline by adhering to the inside wall of thepipeline once the tool has stopped in the position where action is to betaken.

The sealing means may be used in order to brake the movement of the toolby rubbing against the inside wall of the pipeline.

The sealing means may also be used to hold the tool in position bycontact with the inside wall of the pipeline.

Conversely, it is possible to use a tool braking system that is distinctfrom the sealing means. By way of example, it could comprise asacrificial gasket that is changed between two uses of the tool, orskids that come into contact with the wall of the pipeline, or indeedwheels that run along the wall of the pipeline and that have brakes.

It is also possible to use a system for holding the tool in positionthat is distinct from the sealing means. By way of example, this systemcould comprise metal jaws.

FIG. 4 shows the tool 1 moving in a fluid transport pipeline 200. Thefluid may be a liquid or a gas. The pipeline may be buried, in the openair, or it may pass under the sea or under a lake.

The tool is previously inserted via a launch station (not shown), i.e.pipeline equipment that conventionally enables cleaning or inspectiontools to be inserted into the pipeline. Before the tool is inserted, itis verified that the pipeline 200 is pistonable, i.e. that such an itemcan travel along the pipeline without becoming jammed therein. The tool1 has an outside diameter that enables it to travel inside the pipeline200, the guide means 110 being in contact with the inside surface of thewall of the pipeline 200 for guidance purposes. The tool is driven bythe flow of fluid flowing in the pipeline, at a speed that depends onthe extent to which the flap 140 is open and on the flow rate of thefluid. The fluid flows both around the tool 1 and through the inside ofthe pipe segment 100.

FIG. 5 shows the tool 1 stopped at a defect 210 that needs to berepaired in the wall of the pipeline 200. The tool 1 is stopped by itsmouth 101 encountering an abutment 220 that has previously been put intoplace in the pipeline 200 from outside the pipeline. In an embodiment,the abutment 200 is put into place by hot tapping. The method maycomprise welding a socket on the pipeline and then piercing the socketwhile the pipeline is under fluid pressure. In this example, a metal rodis implanted in the tap and forms an abutment inside the pipeline for anitem having the diameter of the tool 1.

The abutment is positioned in the pipeline 200 in such a manner that thedefect 210 faces the section of the pipe segment 100 that lies betweenthese inflatable gaskets 125 and 130 once the tool is in positionagainst the abutment. Furthermore, three taps 240, 242, and 244, eachhaving its own decompression valve, are formed beforehand, or after thetool is in position, each facing a respective one of the sections of thepipe segment 100 between a pair of inflatable gaskets. These taps may bemade by hot tapping.

Once the tool is stopped by the abutment 220, the fluid under pressurecontinues to flow around the tool, and also through the inside of thepipe segment 100. The flap 140 is opened so as to reduce the “windage”of the tool 1.

In FIG. 6, the inflatable gaskets 120, 125, 130, and 135 of the tool 1are shown inflated. Each of these elements comes into contact with thewall of the pipeline to prevent fluid passing around the pipe segment100. Thus, three sealed toroidal zones 310, 320, and 330 are created,each facing one of the taps 240, 242, and 244 fitted with itsdecompression valve. The fluid continues to flow through the inside ofthe pipe segment 100.

Using the valves in the taps 240, 242, and 244, each of the toroidalsealed zones 310, 320, and 330 is then decompressed, with the zone 320between the inflatable gaskets 125, 130 being the main zone in which theaction is to be taken, while the other two zones 310 and 330 serve assealing locks for ensuring that there is no fluid leak into the mainzone from the free zones of the pipeline 200, upstream and downstream.

It is specified at this point that although the embodiment shown thusmakes use of two sealing locks 310 and 330, such locks are not essentialelements, and the invention can thus be performed with only twoinflatable gaskets. Nevertheless, it should be understood that thepresence of these locks is highly advantageous.

It is also specified that although the presently-described embodimentuses three taps, one of the two taps 240 and 244 could be superfluous inthe event of the tool having an internal channel enabling fluid to flowbetween the locks 310 and 330 formed by the gaskets.

FIG. 7 shows the repair 212 to the defect 210, which repair mayconstitute welding a patch to take the place of the defective portion ofthe pipeline or making a repair by building out by welding, or by someother type of repair. This is done without pressure, and possibly afterdraining the fluid through the tap 242. Repair is preferably performedby taking action from the outside of the pipe, by an operator or by anapparatus.

After the repair process, the inflatable gaskets 120, 125, 130, and 135are deflated, and the entire pipeline 200 is thus put back underpressure, including in the zones 310, 320, and 330. As can be seen inFIG. 8, the abutment 220 is moved so that it no longer retains the tool1 in the pipeline, and the tool 1 continues to travel in the flowdirection of the fluid, at a speed that is determined by the extent towhich the flap 140 is open and by the flow rate of the fluid, which flapis opened in order to be able to recover the tool quickly in an arrivalstation of the pipeline. At this stage, it is desirable to close off thetaps 240, 242, and 244.

The invention is not limited to the embodiments described, but extendsto any variant coming within the ambit of the scope of the claims.

By enabling the wall to be isolated from the fluid, the tool makes itpossible in particular to perform a welding operation on pipelines inwhich the forced convection generated by the fluid would lead toexcessive cooling that would be harmful for the mechanical soundness ofthe welding bead. This phenomenon can be encountered in certainpipelines as a function of the diameter, of the flow rate, and of thetemperature of the fluid. Welding can thus be carried out with orwithout decompression of the zone that is sealed off by using the tool.

What is claimed is:
 1. An intervention method for acting on a wall of afluid pipeline using a tool, the method comprising: moving the toolinside the pipeline until a pipe segment of the tool is positionedfacing a zone of the wall of the pipeline; creating sealing upstream anddownstream from the zone using first and second seals of the tool so asto seal off an outer portion of a segment of the pipeline around thezone; and acting on the zone of the wall; wherein the sealing by thefirst and second seals occurs in two portions of the pipeline so as todefine a sealing lock between the two portions of the pipeline; andwherein the tool further comprises an adjustable propulsion systemconfigured to make use of movement of the fluid in order to move thetool.
 2. The intervention method according to claim 1, wherein the firstand second seals comprise expandable and retractable sealing gasketsthat are actuated in expansion to create the sealing and that areretracted after action has been taken.
 3. The intervention methodaccording to claim 1, wherein the tool is propelled in the pipeline bymovement of a fluid.
 4. The intervention method according to claim 1,wherein the movement of the tool in the pipeline and the creation of thesealing are remotely controlled.
 5. The intervention method according toclaim 1, wherein: positioning of the tool in the pipeline is performedusing an abutment placed inside the pipeline; and the method furthercomprises hot tapping the pipeline in order to put the abutment intoplace.
 6. The intervention method according to claim 1, wherein: theouter portion of the segment of the pipeline is decompressed using avalve; and the method further comprises hot tapping the pipeline inorder to put the valve into place.
 7. The intervention method accordingto claim 1, wherein the first and second seals are used to brake themovement of the tool by rubbing against the wall of the pipeline.
 8. Theintervention method according to claim 1, wherein the first and secondseals are used to hold the tool in position facing the zone by makingcontact with the wall of the pipeline.
 9. The intervention methodaccording to claim 1, wherein acting on the zone of the wall comprisesmaking a repair with a welded patch, a repair by build-out welding, or arepair by welding on an outside surface of the pipeline.
 10. Theintervention method according to claim 1, further comprising:decompressing the sealing lock using a valve.
 11. The interventionmethod according to claim 1, wherein the adjustable propulsion systemcomprises one or more flaps, one or more diaphragms, or one or moreadjustable grids installed in the pipe segment.
 12. The interventionmethod according to claim 1, further comprising: braking the tool untilthe pipe segment of the tool is positioned facing the zone of the wallof the pipeline.
 13. The intervention method according to claim 1,further comprising: holding the tool in position by contact with thewall of the pipeline.
 14. The intervention method according to claim 13,wherein holding the tool is performed by a system that is distinct fromthe first and second seals.
 15. An intervention tool for taking actionon a wall of a fluid pipeline, the intervention tool comprising: a pipesegment configured to be positioned inside the pipeline; and first andsecond seals configured to create sealing between the wall of thepipeline and the pipe segment in order to isolate an outer portion of asegment of the pipeline from fluid; wherein the first and second sealsare configured to be positioned in two portions of the pipeline so as todefine a sealing lock between the two portions of the pipeline; andwherein the tool further comprises an adjustable propulsion systemconfigured to make use of movement of the fluid in order to move thetool.
 16. The intervention tool according to claim 15, wherein the firstand second seals comprise expandable and retractable sealing gaskets.17. The intervention tool according to claim 15, further comprising: aguide system configured to guide movement of the tool inside thepipeline.
 18. The intervention tool according to claim 17, wherein theguide system comprises at least one wheel or deformable disk at each endof the pipe segment.
 19. The intervention tool according to claim 15,further comprising: a braking system configured to brake the tool. 20.The intervention tool according to claim 15, further comprising: asystem configured to hold the tool in position by contact with the wallof the pipeline.
 21. The intervention tool according to claim 20,wherein the system configured to hold the tool in position is distinctfrom the first and second seals.
 22. The intervention tool according toclaim 15, further comprising: a system configured to enable the tool tobe located and controlled remotely.
 23. The intervention tool accordingto claim 15, wherein the adjustable propulsion system comprises one ormore flaps, one or more diaphragms, or one or more adjustable gridsinstalled in the pipe segment.